Proposed Approach: We will develop a novel 24-state cohort of injured children presenting to emergency departments (EDs) over an 8-year period. We will then use this research data resource and an inter- disciplinary team to describe and evaluate the value of ?pediatric readiness? in the emergency care of injured children. Importance: Unintentional injury remains the leading cause of death and years of potential life lost in children. Use of emergency services following injury is common, with large variability in the readiness to care for injured children. While several national and state efforts have sought to improve pediatric readiness, it remains unclear whether increased readiness improves quality and health outcomes, and at what cost. This project seeks to build a unique data resource for the scientific community and to use this resource and an inter-disciplinary team to rigorously evaluate the emergency care system for injured children in terms of quality, outcomes and costs. This project will fill key scientific gaps in pediatric trauma care and seeks to identify a re-engineered, high-value emergency care system for injured children that optimizes quality, outcomes and costs. Objectives: The proposal has 3 specific aims: Specific Aim 1. To build a novel 24-state research data resource and use these data to describe and quantify the emergency care of injured children in the context of pediatric readiness, including out-of-hospital, ED and inpatient care. Specific Aim 2. To evaluate how pediatric readiness affects the quality of care, health outcomes and costs of care for injured children. Specific Aim 3. To assess the value of pediatric readiness in the emergency care of injured children, including the balance of quality, outcomes and costs. Study Design: This will be a cohort analysis of a 24-state, population-based cohort of injured children presenting to 2,280 EDs in 24 states. Nine unique data sources will be matched at the patient level to create the master dataset. ?Pediatric readiness? will be defined using a variety of EMS, ED and hospital measures. Setting: The setting includes 2,280 hospitals in 24 states, representing diverse facilities, geographic regions, patient demographics, pediatric readiness and systems of care. Participants: The study will enroll 21.6 million injured children 0 ? 19 years presenting to 2,280 EDs following an injury event from 1/1/2012 through 12/31/2019, representing the entire denominator of injured children seeking emergency services in these states. The cohort will include 541,096 children with serious injuries (Injury Severity Score ? 16), representing high-risk patients. Outcome measures: We will evaluate 12 pediatric trauma quality measures, 2 patient-centered outcomes and acute care costs.